Mathematics

Grade10

Easy

Question

# Find two numbers whose sum is 15 and difference is 3.

- 13 and 2
- 7 and 8
- 9 and 6
- 3 and 12

Hint:

### Here we have to solve the system. Given equations are, x + y=15 and x − y=3. Use the basic concept and solve this question by substitution method.

## The correct answer is: 9 and 6

### Here we have to solve this equation,

Firstly, we have given, that the sum of the numbers is 15 that is

(Let the two numbers be x and y.)

x + y=15..........(1)

Also the difference of the numbers is 3 that is

x − y=3..........(2).

Add equations 1 and 2 to eliminate y, because the coefficients of y are opposite. So, we get

(x + x) + (y − y)=15+3

i.e. 2x = 18

⟹x=9

Substituting this value of x in (1), we get

9+y=15

i.e. y=15−9=6

Hence, the two numbers are 9 and 6.

In this question, we have to solve the equation, basically we have to find the value of x & y.